Twisted paper yarn



Feb. 3, 1959 H. A. SCHWARTZ TWISTED PAPER YARN Filed March 26, 1956 INVEN TOR. flweow/l. Scam/e72 wosma @2289 29.5mm NmSNE TWISTED PAPER YARNHarold A. Schwartz, Norwalk, Conn., assignor to Patchogue-PlymouthCorporation, a corporation of New York Application March 26, 1956,Serial No. 574,019

2 Claims. (Cl. 57167) The present invention relates generally to yarnsor cords of twisted paper ribbon and more particularly to an improvedtechnique for manufacturing twisted paper yarn constituted by intimatelybonded or laminated paper ribbons.

It has been known to make rugs and other woven fabrics by the use ofyarns formed by twisting paper strips. To impart body to the fabric itis desirable to employ relatively bulky paper yarns. customarily suchyarns are made bytwisting a cover ribbon about a paper core or filler,the cover or face ribbon being generally made of good quality paper andthe filler of relatively cheap waste paper. Since the cover and thefiller are disconnected elements, the resultant yarn is of poor tensilestrength and subject to frequent breaks in the course of twisting. 1

Accordingly it is the principal object of this invention to provide animproved twisted paper yarn of increased *pension of fibers, as in thecylinder process.

bulk and of superior-tensile strength. Also an object of the inventionis to produce such yarn efficiently and at low cost.

More specifically, an object of the invention is to provide means formanufacturing a twisted paper yarn consuch that breakage in twisting isminimized. The outer.

and more expensive ply is preferably made of thin paper to reduce thecost thereof, whereas the inner ply is of thick paper so that while theresultant yarn is bulky and has the attractive appearance of the coverply, the net cost of the yarn is low.

A significant feature of the invention resides in the face that bylaminating two or more thicknesses of paper web, the tensile strength ofthe resultant sheet is substantially greater than it would have been hadit been fabricated in the same thickness without lamination. Forexample, a laminated sheet of paper whose composite basic weight equals24- pounds would have 110 to 130% of the strength of a single sheet ofpaper whose basic weight is also 24 pounds. Yarn made from ribbons cutfrom such laminated sheets likewise exhibit augmented tensile strength.

Briefly stated, laminated paper sheets in accordance with the inventionare made by means of multi-cylinder or multi-Fourdrinier wet ends. Thusin the case of a cylinder machine, two or more cylinder molds areutilized, each producing a web of paper which is transferred to the wetfelts of the paper machine. Lamination of the two or more webs of papertakes place when the wet webs of paper are brought into intimate contactthrough the pressure of the felts against the various rollers and driersof the paper machine. Neither adhesives nor extreme pres- "ice sures arerequired to effect the lamination, the bonding being effected solely bythe felting action of the two or more wet webs of paper.

Where the chief requirement for the yarn is a high order of tensilestrength, the two or more cylinder molds of the machine may operate inthe same stock chest. On the other hand, these two or more cylindermolds may be arranged to operate in separate stock chests where theresultant web of paper is to have a colored top side and a cheaperunbleached paper for the reverse side. Paper made in this fashion isthen cut into ribbons and twisted into a yarn, the colored side actingas the cover and the inner side as the filler or core.

For a better understanding of the invention as Well as other objects andfurther features thereof, reference is had to the following detaileddescription to be read in conjunction with the accompanying drawingwherein Figure 1 is a schematic view of a cylinder machine for forminglaminated paper in accordance with the invention,

Figure 2 is a schematic view of the ribboning device for paper webs madein the machine, and

Figure 3 is a schematic view of the twisting devices for the paperribbons.

In paper-making a wet web is formed either by spreading a dilutesuspension of fibers evenly onto the surface 'of a moving endless beltof wire cloth through which water may be drained, as in the Fourdrinierprocess, or by running an endless belt of wire cloth through a sus-Fourdrinier process some of the water drains off by gravity, still'moreis removed by suction and the remainder of water is expelled bypressure. In the cylinder process a vacuum is maintained below the stocklevel in the vat in which the cylindrical wire cloth rotates and thepaper web is caused to form on the wire in very much the manner of acake on a vacuum filter. In either process the thickness of a sheet iscontrolled by the speed of travel of the machine, by the ratio of fiberto Water in the stock suspension (i. e., the consistency of the stock),or by the amount of stock allowed to flow onto the machine.

Referring now to Figure 1 of the drawing, there is shown a cylindermachine adapted to carry out the invention, the machine comprising twochambers or vats 1t) and 11, each containing a paper pulp slurry 12 and13. The nature of the stock and its manner of preparation depends on thetype of laminated paper desired. Thus the vat which is to furnish thecover paper will contain a suitable mixture of materials and coloringmatter blended in'the stock suspension so as to form a paper ply of goodquality. The stock in the other vat, however, may be prepared from wastepaper since the ply formed thereby is intended to give bulk to the yarnand will not be visible. The conventional steps involved in stockpreparation, that is, slushing, beating, refining, etc., form no part ofthe present invention except to the extent that they produce paper pliesof the desired quality and thickness.

Rotatably mounted in vats 10 and 11 are respective cylinder molds 14 and15 which serve to pick up thin layers of the paper pulp and apply it toa papermakers felt 16. The felt 16 is supported on rollers 17, 18, 19and 20 which act to carry the felt in continuous movement, the rollersbeing positioned to cause the felt to engage the upper surfaces of thecylinder molds. Squeeze rollers 21 and 22 are arranged to cooperate withcylinders 14 and 15, respectively, the felt 16 running between thesqueeze rollers and the associated cylinders. These rollers perform adual function; they act to force the freshly formed paper pulp laps toadhere to the felt in order that the laps may be conveyed thereby, andthey also serve to squeeze out part of the excess water contained in thelaps.

In the The direction of felt movement is such that it passes first overcylinder and then over cylinder 14 to pick up successive layers or lapsof wet paper pulp. While only two cylinders have been shown to form-alaminated two-ply paper, it is to be understood thata greatennumher ofcylinders may be employed toiormagreater number of plies, as desired. Asthe felt {passes over cylinder 15, a first fiber layer, represented bysymbol 23, is applied thereto and as the felt passes over cylinder ld, asecond layer, represented by symbol 24, is superimposed over the firstlayer to form a sandwich-like web of two freshly formed paper pulp laps.Web 25 travels over roller 18 for conveyance-toward rolier 20 and as itpasses over roller 20, the Wet Web is separated from felt 16 and led tothe press section represented schematically by rollers 26 and from thereto a dryer section 27. It is to be understood that the press and dryersections operate in conjunction with felts for supportingthe paper Webthereon. For purposes of clarity, these felts havebeen omitted in thedrawing.

The wet web entering the press section 26 is constituted by superposedlayers of paper pulp. The press section 26 may consist of a series ofsmall press rolls each with its ownvfelt system, followed by a mainpress roll, whereby the pressure applied to the web .is increased insuccessive steps. The press section acts in the presentinventionnotmerely to reducethe water content of the web but alsofurtherto effect an integral bonding or felting together ofthe separate layers.Under pressure .the wet fibers of the separate laps are caused tointerlock such that when the web is dried, the laps or plies areinseparable. Along with the dewatering, the wet pressing compacts andreduce the surface inequalities in the sheet without, however, adverselyafiEecting its structure.

The sheet emerging from the press section now passes the dryer cylinders27. 'The number and size of these cylinders depends on the amount ofwater which has to be removed in a given time, this being a function ofmachine speed and weight. The dryer cylinders are preferablysteamhe'atedftoexpedite the removal .of the water.

As the sheet leaves the last dryer cylinder, itthen passes through aseries of heavy metal rolls which calendar it under high pressure toimprove the smoothness and finish of the sheet. Then, as shown in Fig.2, the laminated paper sheet goes through suitable slitters 28 whichserve to cut the sheets into ribbons of any desired width, the ribbonsbeing wound into suitable rolls 29.

The roll 29 of laminated paper, as shown in Fig. 3, may be passedthrough a water bath 30 and then run directly into a twisting machine toform a cord or yarn of paper with the quality paper on .top and thecheap unbleached paper on the inside as a .filler. The wetting of thepaper tape prior to twisting facilitates curling and causes the paper totake a set and hold the twist when it dries. Instead of wetting thetape, it may first be passed through a steam box so that the tapes canbe twisted in a warm, moist condition. Sizing material may also be addedto the water bath to improve the water and scuif resistance ofthe'twisted yarn.

The present invention makes possible a twisted paper laminated yarnhaving less cover than prior art multiribbon yarns, the laminated yarnbeing characterized by superior tensile strength, increased efficiencyand less waste. It is possible, forexample, to use a waste paper innerply of 20 pound weight and a colored outer ply of good quality paperhaving a 1.0 pound weight, so that the net weight of the twistedyarns is30 pounds. Since the bulk of the weight is in the cheap paper, eventhough the yarn has the appearance" of the expensive paper the cost ofthe combination is relatively low.

It will be obvious that the concept disclosed herein in connection witha cylinder machine may be applied to other paper-making devices such asthe 'Fourdrinicr machine.

While there has been shown what is considered to be a preferredembodiment of the invention, it will be manifest that many changes andmodifications may be made therein without departing from the essentialspirit of the r invention. It is intended, therefore,.in the annexedclaims and thereby form a laminated paper web in which the first lapconstitutes a cover ply and the second lap constitutes a filler ply,slitting said paper .web into ribbons, and twisting said ribbons in adirection exposing the cover ply and concealing the filler ply to formsaidyarn.

2. The method of producing a paper yarn of ,good appearance and body asWell as of high tensilestrength, comprising the steps (if successivelypassing al'paperinakers felt along two cylinder molds to form inasuperposed relation 'a'first we'tlap er thin and gooid'quali'ty paperstock-and a second .wet. lap ofrelatively bulky and poor quality paperstock, pressing and drying said superposed laps integrally to bond sametogether and thereby form a laminated paper web in which thefirstlapconstitutes a cover ply and the'second lap constitutes lafiller ply,slitting said 7, paper web into ribbons, andtwisting said ribbons in adirection exposing the'cove'r ply-and concealing the filler ply to formsaid yarn.

References Cited in the file of this patent UNITED STATES PATENTS436,261 Rice Sept. 9, 1890 1,739,038 Millspaugh Dec. 10, 1929 1,853,068Millspaugh Apr. 12, 1932 1,972,607 Strawn' Sept.4', 1934 1,994,057Wallach Mar. 12, 1935 2,388,745 Katz Nov. 13,1945 2,707,368 Pullman "May3, 1955 2,772,994 Lacy Dec. 4,1956

FOREIGN PATENTS 570,109 Great Britain June 22, 1945

